1. Field of the Invention
The present invention relates to a processor system which can perform a data transfer process by DMA (Direct Memory Access), a DMA control circuit, a DMA control method, a control method for DMA controller, a graphic processing method, and a graphic processing circuit.
2. Related Background Art
In conventional DMA transfer, data transfer is performed in parallel with an operation of a host processor to reduce processing load on the host processor. While the DMA transfer is performed, the host processor can perform another process. For this reason, the DMA transfer is suitably applied to a case in which a large amount of data such as image data is transferred.
A DMA transfer is generally performed under the control of a DMA controller. A host processor sets transfer control information representing time when a DMA transfer is performed, a position from which the DMA transfer is performed, and a position to which the DMA transfer is performed in the DMA controller in advance. According to the setting information, the DMA controller performs the DMA transfer.
On the other hand, as a method of increasing the speed of a process in a processor system, there is known a method in which a plurality of arithmetic units are arranged and operated in parallel to each other. In this case, calculation process results of the plurality of arithmetic units are desirably transferred in parallel to each other, and a plurality of DMA controller may be arranged.
However, when the plurality of DMA controllers are arranged to make it possible to perform data transfer processes in parallel to each other, the host processor must set pieces of transfer control information for the DMA controllers, processing load on the host processor increases. The processing load increases in proportion to the number of DMA controllers.